1. Field
The present disclosure relates to a visible light sensitive photocatalyst, and more particularly, to visible light sensitive photocatalyst capable of decomposing water, methods of producing the visible light sensitive photocatalyst, and an electrochemical water decomposition cell and an organic material decomposition system, each including the visible light sensitive photocatalyst.
2. Description of the Related Art
When a photocatalyst receives light having an energy level equal to or greater than a band gap energy, electrons are excited from a valence band to a conduction band, thereby disposing the electrons in the conduction band and forming holes in the valence band. The electrons and holes may diffuse to a surface of the photocatalyst and participate in oxidation and reduction reactions.
Photocatalysis is used to directly decompose water using solar energy to generate hydrogen, which is an alternative next-generation energy source. Photocatalysis may also be used to decompose volatile organic compounds (VOCs), offensive odors, and environmental hormones. Photocatalysts can be used to treat waste water and to treat decomposable refractory contamination materials. Also, photocatalysts can be used to sterilize germs and bacteria. Accordingly, a photocatalyst technology that uses only solar energy at room temperature would be useful for producing hydrogen and for environmental restoration, and is receiving attention for use as a powerful method for resolving environmental contamination.
Titanium dioxide (TiO2) is used commercially as a photocatalyst, and has excellent organic material and water decomposition characteristics. However, TiO2 provides photocatalysis only in response to ultraviolet light, which accounts for about 4% of solar light. Accordingly, to more effectively use the energy available in solar light, it would be desirable to have a photocatalyst material having improved visible light activity to more effectively use visible light, which accounts for about 43% of solar light.